losing your best friend to a guy

Me and my "best friend" have been friends for now a little over 5 years. And then all of a sudden she stops talking to me and then I notice that she doesn't want to hang out anymore because she has a boyfriend. She was the only person I told everything to, even my boyfriend that I had. Since me and now my ex broke up I don't have anyone to talk to about things... What do I do? And does anyone want to talk